Index: firmware/powermgmt.c
===================================================================
--- firmware/powermgmt.c	(revision 31320)
+++ firmware/powermgmt.c	(working copy)
@@ -64,6 +64,8 @@
 
 static bool sleeptimer_active = false;
 static long sleeptimer_endtick;
+/* The number of seconds the sleep timer was last set to */
+static unsigned int sleeptimer_duration = 0;
 
 #if CONFIG_CHARGING
 /* State of the charger input as seen by the power thread */
@@ -707,6 +709,8 @@
 void reset_poweroff_timer(void)
 {
     last_event_tick = current_tick;
+    if (sleeptimer_active)
+        set_sleep_timer(sleeptimer_duration);
 }
 
 void sys_poweroff(void)
@@ -777,6 +781,7 @@
         sleeptimer_active  = false;
         sleeptimer_endtick = 0;
     }
+    sleeptimer_duration = seconds;
 }
 
 int get_sleep_timer(void)